Generally, the precision of a machining tool can be affected by factors including: the static geometry errors and the dynamic thermal error of the tool itself, the wear-and-tear of a cutting tool while being used in a machining operation, and the thermal deformation happened on a workpiece that is being machined. According to prior studies, thermal deformation is responsible for about 40% to 70% of machining errors of a machining tool, so that the thermal behavior of a machine tool can be used as a performance index for measuring the precision and stability of the machine tool. That is, if the thermal behavior is repetitive and stable, the machine tool is able to maintain a good machining quality for a sustainable long period of time; otherwise if the thermal behavior is varying significantly, there may be thermal induced deformation on the structure of the machine tool, that can further cause displacement or deform to a cutting end of the machine tool, and consequently the machining quality of a workpiece that is being machined by the deformed cutting tool can be seriously affected as the required geometry accuracy and surface texture on the workpiece can not be met.
It is noted that for reducing the adverse affect of thermal deformation, cooling fluid, such as a cooling oil, is commonly being used for enabling heat exchanging between a cutting tool and a workpiece being machined. Operationally, the cooling fluid is pumped to a chiller where it is chilled down before being guided to flow through a structure for cooling, and then the cooling fluid is drown to flow back to an oil tank to complete a cooling cycle. However, despite the heat exchanging enabled by the use of a cooling fluid is easy to operate and apply, it is difficult to control the heat exchanging to be happened at a specified position and thus the cooling position could only be adjusted according to user experience. Consequently, the efficiency of heat exchanging between a cutting tool and a workpiece is poor, and there can be thermal deformation being induced to a structure that is being cooled by the varying cooling fluid as the temperature change of the structure is not stable. Not to mention that it is difficult to pin point a position of maximum hot spot on a workpiece for heat dissipation; the flowing of the cooling fluid on the portion of the workpiece that is not being machined could cause shrinkage to the portion of the workpiece; the temperature raising to the cooling fluid after heat exchanging can cause temperature difference to the structure which can induce certain thermal error; and the machining operation using cooling fluid could be very costly as the cooling fluid is generally limited to a specified lifespan and required to be changed regularly.
In addition, currently there are infrared thermometers being used for sensing temperature of an object, whereas the infrared thermometers could convert the radiant infrared energy emitted from the object's surface to an electrical signal that can be displayed in units of temperature after being compensated for ambient temperature. However, the operation of such infrared thermometers rely heavily on the use of proper temperature calculation unit for ambient temperature compensation, otherwise reading of the infrared thermometers may be subject to error due to the reflection of radiation from ambient environment. Moreover, the infrared thermometers that are current available on the market can only display temperature without the ability to enable a certain posterior processes according to the temperature detection.
Therefore, the focus point of the present disclosure is to develop a machining thermostatic control system and a method of using the same, and more particularly, to a machining thermostatic control system capable of reducing thermal error by using a temperature signal that is obtained from a means of temperature calculation to adjust outlet direction, flow and temperature of a cooling fluid for enabling a heat exchanging operation to happen at a position of maximum hot spot of a workpiece that is being machined at a high speed.